Voltage stabilizer



n.lw, MUHm" f VOLTAGE STABlLIZE i Filed Apil. 15, 1924 3 Smets-@wt 2 C F Bm @wmf www wle-mim n A @far/ffm 1M fm1/wm@ @www f 042g v my 27,1926. x 1593,59@

J. W. MURRY y VOLTAGE 'STABLiZER Filed April 15, 192.4 3 Sheei-,s-Sheet s FEE. Kik.

Patentedduly 2'l7, 1926.

AUNITED STATES 1,593,590 PATENT OFFICE.

JAMES W. MURRY, F BROOKLYN, NEW YORK.

VOLTAGE sTABILlzna application nea April-15, 1924. serial No. 708,719.

My invention'relates to electrical `installations, and particularly to those in which a direct current is caused to flow in a given.

circuit.' It consistsfin means for eliminating from the voltage under which such a current flows, fluctuations, such as may exist age under whichthe current employed to i energize the receiving apparatus of a wireless telephony system, ows, and in that particular application I shall describe it.

But the fact will be plain that the radio receiver or sender is amere instance of an opportumty for advantageous use of the 1n- .vention, and that the invention in its broader and more general aspect is by no means limited to this particular application.

The accompanying diagrams will serveto illustrate the application of the invention to the wireless service indicated above and the practical consequence and effect of such application. Fig. I shows the component electrical units and their connections, when my invention is employed in application to a radio receiver of typical form or type. Fig. II is a chart on a system-of co-ordinates illustrating voltage variation .and illustrating the effect. of the presence of my invention, to

negative and eliminate voltage variation. Fig. III is a'vector diagram, illustrating in another way the same matter. Fig. IV is a dia am similar to Fig. I and illustrates a mo ification in the application of the invent.' )11. Figs. V, VI, and VII illustrate other modilications.

In a radio receiver or sender employing an electron tube both the plate circuit and filament circuit require for successful servy ice a current owing under a substantially constant voltage to energize the receiver. Commonly a battery is employed to afford such a current, but 1t is very desirable to be able to dispense with a battery and to energize the receiver with current derived from the familiar domestic supply. The difficulty, insurmountable hitherto, preventing the use of the familiar domestic supply for this purpose is that, whether supplied as direct current or supplied as alternating current and rectified, voltage variations are of such dimensions asto render its use unsatisfactory and impractical.

Fig. I shows 4a yline of Vflow from A through a resistance unit B, to C, and through this line a direct current may, it will be understood, be caused to fiow. A shunt line leads from an adjustable tap D in the resistance unit B, through a detector tube. E to the main line againat F. As thus .far described, the How of current through the shunt line D-E-F is obviously sub- -ject to whatever variations in voltage there may be under which the current is supplied. This condition is indicated. in Fig. II, where a waved line G-H indicates a voltage varying from time to time through a range of twenty volts, from a potential of 90 Volts to 110. The variation is here shown to be recurrent and regular in periodicity and in value, but it will appear as I proceed that my invention is not conditioned by such circumstances,'but is applicable to correct any variation, regular or otherwise.

Returning to I, my invention is found in the provision of two transformers I and J, of which the primaries are included in shunt lines between the points A and C, and the secondaries are included in the line of flow already specified, from A to the resistance unit B and thence through the shunt line D-E--F. The secondary coils are, in relation to the normal line of flow A-B-D-E-F, oppositely arranged, to the end that the voltages induced in these two coils ,'(whatever their particular values may be) shall be induced with opposite effeet upon the current otherwise normally owing in the line A-B--D-E-F. That is to say', in one transformer the induced voltage is added to the normal voltage and in the other it'is substracted from the normal voltage. This condition of oppositely acting 4induced voltages is indicated bythe two dotted arrows set opposite the two transformers I and J in Fig. I.

I so particularly proportion the resistance and reactance ofthe primary windings of the two transformers I and J that the transchanges, the two transformers will become active. Suppose the change to be by way of increase, the increment being sayQO volts,--from 90 volts to 110. One of the transformers, the transformer J, will tend to augment the variation, making it greater;

that is to` say, transformer J 'tends to inj crease the voltage to a value greater than.

j 110 volts. The other transformer, the transformer I, sets up a countervailing voltage, greater than lthe accession. The accession in value is 20 volts. The effect of transformers I and J then is to impose on the line an alternating voltage of 20 volts. But this imposed voltage is opposite in direction to the variations in the applied voltage, and the consequence and effect is to reduce what otherwise would be a varying voltage with a maximum value of 110 volts, and to afford a resulting unvarying voltage of 100 volts, the desired result. Deliciencies in'voltage will similarly be rectified and always, transformers I and J be ing present, the effective voltage through the shunt line D-E-F will be constant, and that is the desired result.

Referring again to the chart, Fig. I-I, the waved line G--H represents the voltage of the line as, but for my invention, it might rise and fall. The consequence and elfect of the presence of the transformers I and. J is to setup a countervailing variation of voltage, indicated by the dotted and oppositely waved line X-Y. This dotted line indicates the aggregate, the sum of the voltages set up lby the transformers. This countervailing voltage will cancel Ithe voltage variations otherwise existing. The re suit will be that the voltage will at all times remain normalas indicated by the straight line G-H.

Turning to Fig. III, the diagram to the left indicates the effect of transformer I alone. Here the arrow KL indicates an alternating voltage equal to the difference between the applied voltage and the steady average voltage. On Fig. II it is the difference between applied voltage and the straight line G-H representing the steady average voltage. K-M and K-N are the component variations inthe voltage, K M is the inductance drop, K-N is the resistance drop, and K-O, opposite in direction to K-M and greater than K-M, represents the voltage induced in the secondary. The next diagram similarly illustrates the ef- :testeo fect of transformer I alone. KMII is as before the variation in .the applied voltage which makes the transformer active. I-P and II-Q are the componentsy of this voltage, K-IJ in the inductance drop, K-*Q in the resistance drop, and lied?. indicates in value and direction 'the voltage induced in the secondary. The third diagram, the diagram to the right, shows the combined effect of trz'insformers I and J. The resultant of forces KO and K--It is K-S, and Il-S is equal in value and opposite in direction to If-ll|, the initial disturbance. Thus voltage disturbance is reduced to zero and eliminated.

It will of course be understood that the component units of the transformers, primary and secondary, and the resistances T,

U, are adjustable, within the lmowledge and skill of the art, to accomplish with practical precision that which is theoreti cally plotted and illustrated in the charts. Thus I indicate in Fig. I adjustment in the secondary of transformer J and also' in the resistance U of the same transformer. Given these two adjustment devices, the apparatus can be suited to existing condi'- tions, whatever they may be.

I have, as a practicall illustration, shown countervailing, oppositely acting transformers, whose effective transformation ratios are 1211/2 and 1:12. It will be 'understood that the essential thing is to achieve a difference (oppositely acting) between t-he induced voltages, equal (approximately) to the variations in the applied voltage. Any particular' values for these transformation ratios, such as to maintain that difference, will, manifestly, achieve, and be within the contemplation of, my invention.

It is not in all cases requisite to make correction and to eliminate voltage with such nicety and with such completeness as is achieved by the apparatus illustrated in F ig. I. In a sender or in a receiver of a radio installation, when the incoming radio waves are strong, or when a. loud speaker is to be operated, such nicety of result may exed the necessity. In such case the arrangement lOl rent flows in the primary and opposite in direction. That is to say the transformation ratio in Fig. IY is 1 :1. This is a simple arrangement. but incapable of completely smoothingv out variation in voltage of the supplied current. The reason, why this arrangement is incapable of completely elim# inating voltage variations, is because the for many applications inconsequential.

vby the arrow lil-di; the voltage of the sec ondary lies in the direction indicated. by the arrow I-U (though the value isnot K-g the value is equal to lie-Il). But Iii-Ii and Iiiare not exactly opposite in direction. There is a small failure of complete balance. But, as I have said, the margin is slight acid @o that practically and for many purposes I may in the practice of my invention use a 1 single transformer, vas illustrated in Iiig. IV,

although for precision the more perfect balance realized in the use of tv'o transformers, as illustrated in l3`igM I, is desirable.

While I have shown vthe use of two sepa'- rate transformers in the description of this device, it will be understood that similar results'can be obtained by combining the two in such a way vthat the two primaries are as before, and, a single secondary winding embraces the magnetic circuits of both transformers. This is diagrammatically illus# trated in Fig. .V. Here two primaries, I

and J, have their secondary in common, and this secondary is in the line of flow from A to the apparatus to be energized, -in this case a radio receiver.

The transformer may be an auto-transformer. In Fig. VI I show two transform-` ers (in that respect adopting the' arrangement of Fig. I) ut one of the transformers, the transformer I2, is here indicated to bel an auto-transformer, having its primary andr secondary windings connected 1n series.

Fign Vil shows the arrangement of but here again the transformerl IV is replaced by the auto-transformer claim as my invention.

l. voltage stabilizer for directif* 'flow includ'iig, in conibinaticinin a circuit of three branches each of which is arranged in shunt relatively 'to the others, two transformers, the primaries of the transformers being arranged one in each cf two of the three branc hes,and the secondaries of the transformers being arranged in series and oppositeltr with relation oneI to the other in the third of the three said branches.

2. A voltage stabilizer for direct-current iiow including, in combination., in a circuit of three branches each of which is arranged in shunt relatively to the others,.two transformers, the primaries of the transformers being arranged one in each of two oilthe three branches, and the secondaries'of the transformers being arranged in series in the third of the ythree said branches and oppositely with respect one to the other,A one. of said transformers being of adjustable value.

' 3. A vmethod of stabilizing the voltage of a direct current flowing in a conductor which consists in imposing upon the current. as it flows two increments of induced voltage'induced by variation in the voltage of the current to be stabilized, the two increments being opposite in direction and when aggregated with the variation in thev voltage of the current to be stabilized effecting cancel-4 lationthereof.

In testimony whereof I have hereunto set my hand.

A JAMES W. MURRY. 

